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From: "RasikaSrinivasan@gmail.com" <rasikasrinivasan@gmail.com>
Newsgroups: comp.lang.ada
Subject: Interfacing to C
Date: Thu, 24 Dec 2009 01:46:05 -0800 (PST)
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Date: 2009-12-24T01:46:05-08:00
List-Id: <comp.lang.ada>

I am building an interface to a C library. This library uses structs
like the following:

typedef struct {
    x : int ;
    y : int }  MyStruct ....

While passing variables of this type to functions, the convention in C
is to pass by value (best of my knowledge).

however when I import a function like:

type MyStruct is record ..... end record ;
pragma Convention(C,MyStruct);

procedure process(var : MyStruct);
pragma Import(C,process);

It appears that Ada passes the var by reference. (Well - I am not able
to tell for sure - just that modifying the binding as follows :

procedure process(varx : int; vary : int);
pragma Import(C,process) ;

works and the previous binding did not.

So the question is - how c(an I force Ada (gnat) to pass a record by
value?

thanks for pointers, srini